Overview of issues related to imatinib therapy of advanced gastrointestinal stromal tumors: a discussion among the experts.

Information regarding the activity of imatinib in patients with metastatic gastrointestinal stromal tumors (GISTs) has accumulated rapidly. Nevertheless, several important issues about imatinib therapy as well as these tumors themselves remain to be answered. Importantly, the optimal dose and duration of imatinib therapy are unknown, with daily doses of 400 mg and 600 mg producing comparable response rates in a phase II study. Moreover, the role of surgery following maximal responses to imatinib and those of functional imaging and use of biopsies in monitoring treatment responses need to be investigated. Further understanding of the molecular and pathologic characteristics of GISTs that are responsive or resistant to imatinib is also needed. This paper summarizes a symposium that was held in Helsinki, Finland, in September 2001.